In the related art, when a crime or a legal dispute relating to a computer such as unauthorized access or confidential information leakage occurs, means or a technique for collecting and analyzing devices, data or electronic records necessary for cause examination or criminal investigation to clarify legal evidentiality has been proposed.
Further, in a US civil suit, since eDiscovery (electronic discovery) or the like is required, both an accuser and a defendant in a lawsuit should submit related digital information as evidence. Thus, digital information recorded in a computer or a server should be presented as evidence.
On the other hand, in the current business world, since most information is prepared by a computer due to the rapid development and spread of IT technology, a large amount of digital information is oversupplied even in the same company.
For this reason, in the course of performing preparation work for producing evidentiary materials for a court of law, an error in which even confidential digital information that is not necessarily related to a lawsuit is included as the evidentiary materials may easily occur. Further, confidential document information that is not related to the lawsuit may also be produced.
In recent years, a technique relating to document information in a forensic system has been proposed in PTL to PTL 3. PTL 1 discloses a forensic system that designates a specific person from at least one target person included in target person information related to a document submission order, extracts only digital document information that is accessed by the specific person based on access history information relating to the designated specific person, sets accessory information indicating whether each of the document files of the extracted digital document information is related to the lawsuit, and outputs a document file relating to the lawsuit based on the accessory information.
Further, PTL 2 discloses a forensic system that displays recorded digital information, sets target person specifying information indicating which person among target persons included in target person information each of the plurality of document files relates to, sets the set target person specific information to be recorded in a storing unit, designates at least one target person, retrieves a document file in which the target person specific information corresponding to the designated target person is set, sets accessory information indicating whether the retrieved document file is related to a lawsuit, and outputs the document file relating to the lawsuit based on the accessory information through a display unit.
In addition, PTL 3 discloses a forensic system that receives designation of at least one document file included in digital document information, receives designation of a language for translating the designated document file, translates the document file in which the designation is received into the language in which the designation is received, extracts a common document file that represents the same content as that of the designated document file from the digital document information recorded in a recording unit, generates translation related information indicating that the extracted common document file is translated by quoting the translation content of the translated document file, and outputs a document file relating to a lawsuit based on the translation relevance information.